The invention relates to a color motion picture print silver halide photographic film, and more particularly to such a film which has an enhanced tonescale optimized for flesh tone and shadow detail reproductions.
Color negative origination silver halide photographic films are a class of photosensitive materials that map the luminance (neutral) and chrominance (color) information of a scene to complementary tonal and hue polarities in the negative film. Upon exposure and development of the film to form dye images from photographic couplers incorporated in the film, light areas of the scene are recorded as dark areas on the color negative film, and dark areas of the scene are recorded as light areas on the color negative film. Colored areas of the scene are typically recorded as complementary colors in the color negative film: red is recorded as cyan, green is recorded as magenta, blue is recorded as yellow, etc. In order to render an accurate reproduction of a scene, a subsequent process is necessary to reverse the luminance and chrominance information back to those of the original scene. In the motion picture industry, one such subsequent process is to optically print (by contact or optics) the color negative film onto another negative working photosensitive silver halide material which produces dye images upon exposure and development, such as a motion picture silver halide print film, to produce a color positive image suitable for projection.
Historically, color print silver halide photographic materials, such as EASTMAN EXR Color Print Film 5386(copyright), have been optimized to yield pleasing projected prints when used in conjunction with color negative origination silver halide photographic materials as discussed above. That is, the sensitometric properties of print materials are co-optimized by considering the properties of the printing device to be used and the nature of a representative color negative tonescale to be printed, such as that of KODAK VISION 500T Color Negative Film 5279(copyright). When a motion picture color negative is printed on motion picture color print stock, the sensitometric properties of the two materials combine to yield an acceptable scene reproduction in the print film when projected on a theater screen. To facilitate obtaining optimal reproductions, guidelines exist regarding the exposure of the camera original negative (for example see American Cinematographer Manual, Dr. Rod Ryan Ed., 7th Edition, The ASC Press, Hollywood, Calif., 1993, pp128-141.), exposure of the print stock (LAD-Laboratory Aim Density KODAK Publication No. H-61), and projector/screen luminance levels (Society of Motion Picture and Television Engineers (SMPTE) Standard 196M-1995).
In order to obtain a high quality visual image in an optical photographic print, the contrasts for each color record of the negative film and print film designed for producing optical prints are typically maintained within certain ranges (e.g., mid-scale contrasts of about 0.45-0.7 for negative films and about 2.5-3.1 for print films). Higher contrasts generally result in less preferred flesh tone reproductions and loss of shadow detail. Lower contrasts may improve flesh tone reproductions, but also may result in production of flat-looking positive print images with black tones rendered as smokey-grey and white tones rendered as light gray. Pictures such as these would not be pleasing to view and would be deemed to be of low quality in the industry.
Correct exposure of camera negative originals has long been emphasized not only to ensure that critical scene information is properly recorded but also so that when the negative is printed on a photographic print film according to trade practice, scene blacks are sufficiently dense in the resulting projected prints. To provide sufficient black densities, the maximum equivalent neutral (i.e., visual) densities obtainable for a silver halide photographic print film should generally be at least about 3.3, and more preferably at least about 3.5, where the Equivalent Neutral Density of any particular dye color record is defined as the visual density that results when the other two dyes are added in quantities just sufficient to produce a neutral gray (see, e.g., xe2x80x9cProcedures for Equivalent-Neutral-Density (END) Calibration of Color Densitometers Using a Digital Computerxe2x80x9d, by Albert J. Sant, in the Photographic Science and Engineering, Vol. 14, Number 5, September-October 1970, pg. 356).
Color photographic silver halide motion picture print films are typically optimized for the direct or release optical printing of color photographic silver halide negative films. Such motion picture silver halide photographic print stocks are accordingly designed with latitudes commensurate for use with typical color negative photographic film dynamic ranges, typically 1.5 printing density or less. The upper-scale contrast of most conventional photographic silver halide print stock is such that lighter densities on the recorded negative map to a region of decreasing contrast in the print stock, preventing the achievement of high print densities that may be desirable for improved reproduction of scene blacks. U.S. Pat. No. 5,888,706 discloses motion picture print films which have significantly higher upper-scale contrasts in combination with conventional midscale contrasts, which enables high black densities and improved color saturation, while also maintaining reasonable flesh tone and shadow-detail reproduction.
One solution available to photographers and cinematographers for improving flesh tone reproduction in a reproduced image is to lower the gamma of the color negative origination and/or print photosensitive materials. There are two currently available methods for lowering gamma. The first method of achieving lower overall gamma with silver halide based films is by reducing the development time and/or temperature outside the specifications provided by the manufacturer, a condition known as under-development. One way this is practiced in the art is to empirically plot gamma against development time. From the results, an appropriate development time is chosen. Gamma is calculated from a plot of density versus log E. This is described in The Manual of Photography by Ralph E. Jacobson, Focal Press, 1978. The second method to lower the gamma in the photosensitive materials is to alter the exposure protocol, specified by the manufacturer, with a technique called xe2x80x9cflashing.xe2x80x9d With this technique, a film is exposed to a weak, but uniform, level of light prior to development. The exposure can be applied either before or after exposure to record the desired image. The level of light that must be used is determined by an empirical, trial-and error procedure. This is described in American Cinematographer Manual, 6th edition, The ASC Press, 1986 and in Motion Picture Film Processing by Dominic Case, Focal Press, 1985. Neither of these strategies, however, will fully maintain desired blacks and whites reproduction from the original scene to the viewed image.
U.S. Pat. No. 5,674,665 discloses a relatively low contrast color negative origination photosensitive material which provides the ability to record original scenes and create viewed images with a large range of subject luminance and low contrast, and with blacks and whites from the original scene reproduced faithfully, without the need for special exposing and/or processing conditions. Not all scenes are captured on origination film having such characteristics, however, and such advantages are accordingly not available when printing a scene recorded on other negative film stocks onto available motion picture print films.
It would be desirable to provide motion picture print films which enable improved flesh tone reproduction and image shadow detail, while maintaining sufficiently high black densities in projected prints. The overall contrast of color-coupled silver halide photographic print materials may be lowered to improved flesh tone reproductions by either changing film silver laydown and/or coupler levels or through modification of film processing conditions. Unfortunately, in doing so, the maximum densities in such lower contrast films would also be undesirably lowered upon conventional printing as discussed above. Thus there is an apparent conflict in establishing an optimal contrast level for photographic print stock: to obtain improved flesh and shadow-detail reproduction, the contrast should be relatively low, but low contrast levels prove to be detrimental to obtaining good black densities. There is a simultaneous need for improved flesh tone reproductions, good blacks and sufficient shadow density.
It would accordingly be desirable to provide a color-coupled silver halide photographic print film element which would provide improved flesh and shadow-detail reproduction, while also enabling sufficiently high black densities and color saturation. It would be further desirable to provide such an element which may be used in current printers and processors to obtain such properties without requiring any modifications to standard exposure and development processes.
One embodiment of the invention comprises a silver halide light sensitive photographic print element comprising a support bearing on one side thereof: a blue color sensitive record comprising at least one blue-sensitive silver halide emulsion yellow-image forming layer, a red color sensitive record comprising at least one red-sensitive silver halide emulsion cyan-image forming layer, and a green color sensitive record comprising at least one green-sensitive silver halide emulsion magenta-image forming layer; wherein the overall contrast (OC) of the green record is greater than 1.7, preferably greater than or equal to 1.75, the mid-scale contrast (MSC) of the green record is less than 2.6, preferably less than 2.5, and the upper-scale contrast (USC) of the green record is from 2.85 to 3.15, preferably from 2.9 to 3.1, wherein the parameter OC for each of the color records is defined as the slope of a straight line connecting a point B and a point C on the characteristic curve of Equivalent Neutral Density versus log Exposure for the color record, where points B and C are located by defining a point A on the characteristic curve at the log Exposure required to attain a density level of 1.0, and points B and C are located on the characteristic curve at exposure values xe2x88x921.1 log Exposure and +0.9 log Exposure with respect to point A, respectively, the parameter MSC is defined as the slope of a straight line connecting a point D and a point E on the characteristic curve for the color record, where points D and E are located at exposure values xe2x88x920.2 log Exposure and +0.2 log Exposure with respect to point A, respectively, and the parameter USC is defined as the slope of a straight line connecting point E and point C.
A further embodiment of the invention comprises a process of forming an image in a motion picture silver halide light sensitive photographic print element as described above comprising exposing the silver halide light sensitive photographic print element to a color negative film record, and processing the exposed photographic print element to form a developed image having maximum green Equivalent Neutral Densities of at least 3.3, preferably at least 3.5. In accordance with preferred embodiments, the elements are exposed and processed to form images with red and blue maximum Equivalent Neutral Densities which are also at least 3.3, more preferably at least 3.5.
Preferably, the elements of the invention and the elements used in the process of the invention have corresponding red and blue OC and USC values which are at least 90% of the green values, and more preferably within xc2x110% of the green values, enabling the production of outstanding projected images having improved flesh tone reproduction and good black densities.
We have found that color print film silver halide photographic elements in accordance with the invention enable the production of outstanding projected images having improved flesh tone and shadow detail reproduction, and sufficiently high black densities.